Central nervous system tumor registration in the Swedish Cancer Register and Inpatient Register between 1990 and 2014

Abstract

BackgroundThe Swedish Cancer Register (SCR) is characterized by excellent quality and completeness overall, but the quality of the reporting may vary according to tumor site and age, and may change over time. The aim of the current study was to investigate the completeness of the reporting of central nervous system (CNS) tumor cases to the SCR.Materials and methodsIndividuals hospitalized for a CNS tumor between 1990 and 2014 were identified using the Inpatient Register; the proportion of identified cases that did not have any cancer diagnosis reported to the SCR was subsequently assessed.ResultsBetween 1990 and 2014, 58,698 individuals were hospitalized for a CNS tumor, and a large proportion of them did not have any cancer diagnosis reported to the SCR (26%). This discrepancy was particularly pronounced for benign tumors and among elderly patients (over 30%). It was substantially lower for malignant brain tumors among adults (10%); moreover, no increase in the discrepancy between the two registers was observed in this group during the study period. Similar findings were found when assessing the concordance between the Cause of Death Register and the SCR. Among CNS tumor patients who were not reported to the SCR, a large proportion had only one hospital discharge diagnosis containing a CNS tumor (35%) and were less likely to be found in the Outpatient Register, which indicates that a large proportion of patients may have received an erroneous diagnosis.ConclusionWhile a large proportion of CNS tumor patients were not reported to the SCR, the discrepancy between the SCR and the Inpatient Register was relatively small for malignant brain tumors among adults and has remained stable throughout the study period. We do not recommend that data from the Inpatient Register are combined with the SCR to estimate CNS tumor incidence, without proper confirmation of the diagnoses, as a considerable proportion of CNS tumor diagnoses registered in the Inpatient Register is unlikely to reflect true CNS tumors.

Five-year survival in patients with Glioblastoma is overestimated in registry data - A nationwide population-based Swedish survey during 1958 - 1999

“…Furthermore, no review of pathology was made adding additional uncertainty of the actual numbers of veyear survivors. Given that completeness of registry data is less in older patients for brain tumors our estimate might still be too high [50]. Notably, thirty-ve patients (0.27%) lived more than ten years after diagnosis which is in proximity to data from a systematic review on ten-year survivors of 0.71 % [52].…”

“…However, in the later survey there was a tendency of underreporting tumours of the nervous system, especially in elderly patients over 70 years. In a recent study reviewing malignant brain tumours in the registry between 1990 -2014, the completeness was approximately 90 % in the younger population (< 70 years) but considerably less in elderly patients (> 70 years), ranging between 65-75 % [50].…”

The risk of developing a meningioma during and after pregnancy

“…The Swedish cancer registry employs a system of dual reporting by pathologists and clinicians and has a complete coverage of all histologically verified meningiomas, detected either at surgery or at autopsy. However, patients with conservatively managed meningiomas are reported only by the clinicians who establish the diagnosis; there is also evidence of underreporting of benign brain tumors to the Swedish cancer registry 49 . Nonetheless, there is no a priori reason to suspect selection bias since indications for surgery during the long follow-up period will not be influenced by a history of pregnancy.…”

Estimates of lung and pancreatic cancer survival in Sweden with and without inclusion of death certificate initiated (DCI) cases

“…While earlier investigators have addressed the underreporting of cancers with a poor prognosis in Sweden [14][15][16][17], this is the first study based on comprehensive processing of death certificates including trace-back with diagnostic validation at the source, i.e. medical records.…”